Yes I use dantrell's GNOME 3 without systemd. As I said I would reinvestigate to change to GNOME system.d if it is more stable, future-proof, ... I thought with GNOME without system.d I will have the better solution since Gentoo uses rc.

-) I have read the GDM manual and tried to set with the gconf-editor the /apps/gdm/simple-greeter/recent-layouts variable, but this path is not existing in the editor

-) "I've put "setxkbmap de" (replace de with your layout code) in the last line of /etc/gdm/Init/Default. Works." --> Doesn't work for me.

I believe I have a strange setup for GDM. In my other thread I posted the issue that immediately after login, the system locks me out again. The second login (now with german keyboard!) works. I believe it is only locked...

The user's default session and the language selection are stored in the ~ / .dmrc file. When a user logs in for the first time, this file is created based on the values entered by the user. The user can change these default values each time they log in by simply re-entering. GDM stores these changes for the following registrations.
The ~ / .dmrc file is saved in the INI format. It contains a section called [Desktop], which contains two keys: Session and Language.
The Session key defines the base name of the .desktop file that the user typically wants to use, but without the .desktop extension. The Language key specifies the default language that the user wants to use. If any key is missing, the system-wide default is used. The file normally looks as follows:

Your problem piqued my curiosity, so I have just now installed the GNOME 3 edition of Sabayon Linux (a binary derivative of Gentoo with its own overlay) in a virtual machine. I opted to use Sabayon Linux to investigate your problem because it is quick to install and similar to Gentoo. Sabayon Linux uses systemd rather than OpenRC, but I found that, even with systemd, GNOME 3 in Sabayon Linux exhibits the same problem you are experiencing. So I don't think the problem is specific to dantrell's OpenRC edition of GNOME 3; I think it is a general problem with GNOME 3.

Anyway, I did get GDM to use the German keyboard by default in the end, but it took a bit of messing around to get it to work:

Step 1. I did the usual set up of the German locale that has already been discussed:

Step 3. I used 'Applications' > 'System Tools' > 'Settings' > 'Region & Language' and added the German keyboard under 'Input Sources', and moved 'German' to the top of the list of input sources. It appears to me that it is necessary to move German to the top of the list if you want the German keyboard layout to be the default in GDM.

Step 4. On the panel at the top of the screen, I selected the German keyboard layout, then I logged out.

Step 5. At the top of the GDM greeter screen, I selected the German keyboard layout.

Step 6. At the top of the GDM greeter screen, I then clicked on the Shutdown icon and shutdown the machine.

Step 7. I then booted the machine and the GDM greeter screen now shows German (de) as the default keyboard layout instead of English. I can logout, login, reboot and shutdown, and the keyboard layout on the GDM greeter screen now remains as German. (It took quite a bit of tinkering to get it to work in GNOME 3, which has put me off GNOME 3 even more! )

EDIT: Yep, just proved it to myself: Step 2 is not necessary. The essential step to get German (or any other keyboard layout) to be the default layout on the GDM greeter screen is that it must be at the top of the list of input sources (Step 3)._________________Clevo W230SS: amd64 OpenRC elogind nvidia-drivers & xf86-video-intel.
Compal NBLB2: ~amd64 OpenRC elogind xf86-video-ati. Dual boot Win 7 Pro 64-bit.
KDE on both.Fitzcarraldo's blog

Step 1 & 3 I did already. With only one input source in the Region & Language Settings no selection appears in the top panel. I added a second input source German (Österreich) and now I have the selection menu in the top panel:
-) de1 Deutsch Österreich
-) de2 Deutsch

When I only lock my screen, the GDM greeter shows the selection menu in the panel and I can select german and the german layout works.
But when I completely lock of, no selection menu in the panel is shown. Also after a reboot the menu doesn't appear. I tried both german and german (Österreich) but without success.

I'm not sure, as I don't use GNOME. But googling shows some possibilities. I know you're using dantrell's GNOME without systemd, but some of the things I have found for GNOME with systemd might still be relevant in your case. I notice the following from the documention for the systemd command localectl (see my first post):

Quote:

localectl may be used to query and change the system locale and keyboard layout settings. It communicates with systemd-localed( to modify files such as /etc/locale.conf and /etc/vconsole.conf.

The system locale controls the language settings of system services and of the UI before the user logs in, such as the display manager, as well as the default for users after login.

The keyboard settings control the keyboard layout used on the text console and of the graphical UI before the user logs in, such as the display manager, as well as the default for users after login.

Note that the changes performed using this tool might require the initramfs to be rebuilt to take effect during early system boot. The initramfs is not rebuilt automatically by localectl.

Those do indeed correspond to the language and the keymap at the top of my list (I specified the following 'Inputs Sources': 1. English (UK), 2. English (US) and 3. Portuguese (Brazil)) in 'Applications' > 'System Tools' > 'Settings' > 'Region & Language'.

Notice that GNOME has added the three keyboard layouts ('Input Sources') that I specified in 'Applications' > 'System Tools' > 'Settings' > 'Region & Language'. So you should also edit (or create, if you don't already have an X Windows keyboard configuration file) such a file with the correct settings.

Furthermore, have you tried adding other languages and keymaps to your installation, to see what effect it has on GDM? You can always revert later back to only German if you don't want the additional locales and keymaps. I suggest you try the following:

Step 1. Edit locale.gen as shown below then generate some addtional locales and a new profile:

You can see the list of acceptable locales in the file /usr/share/i18n/SUPPORTED

Step 2. Configure GNOME to specify the language and the list of keymaps ('input sources'):

Use 'Applications' > 'System Tools' > 'Settings' > 'Region & Language' and: a) specify the Language as German; b) specify the Format as Germany; c) add the German, Austrian, British English and American English keyboards under 'Input Sources', and move 'German' to the top of the list of input sources.

Step 3. Check that you have an X11 keyboard configuration file with the correct keymaps:

It works! I created the /etc/X11/xorg.conf.d/00-keyboard.conf and adjusted the order of the keyboard layouts according to Region & Language in the settings. Afterwards changes in GNOME settings were applied in the 00-keyboard.conf and I am able to use the german layout.

An /etc/locale.conf and /etc/vconsole.conf additionally is not necessary when using GNOME without systemd.